The present invention relates to a substrate and mask aligning apparatus and, more particularly, a substrate and mask aligning apparatus for attaining precise alignment by conducting a substrate and mask alignment while checking a state that the mask is aligned actually with the substrate.
In the field of the apparatus that mounts solder balls on solder ball mounting pads on a substrate, such an apparatus is widely used that the solder balls are mounted on the solder ball mounting pads on the substrate respectively, by superposing a mask in which opening portions are provided in solder ball connecting pad portions on the substrate and then dropping the solder ball into the opening portions respectively.
Nowadays a diameter dimension of the solder balls that are mounted on the substrate becomes fine to an extent of about 80 μm. Therefore, positions of the solder balls and a strict aligned state between the substrate and the mask used to mount the solder balls on the substrate cannot be checked with the naked eye. For this reason, the solder ball mounting apparatus capable of checking a mask aligned state with the substrate and a solder ball mounted state on the substrate by shooting images of the substrate and the mask by means of a shooting section such as a camera, or the like, and then processing image data has been provided (see Patent Literature 1, for example).
[Patent Literature 1] JP-A-2005-166859
In aligning the mask with the substrate, in many cases the substrate is aligned with the mask on the basis of alignment information obtained by shooting in advance the substrate and the mask as a single body respectively. In this event, the same mask is used continuously from the beginning as the mask, while the new substrate a shrinkage level and a distortion level of which are different respectively is supplied each time. Also, upon superposing the mask on the substrate, these members are superposed mutually in a state that a tension is being applied to the mask. In such situation, when the mask and the substrate are aligned with each other on the basis of previously picked-up image data of the substrate and the mask, such a problem exists that positions of the pads on the substrate are deviated unexpectedly from positions of the opening portions of the mask.